Pyrrolizidine alkaloids (PAs) are a group of plant secondary
metabolites with carcinogenic and hepatotoxic properties. When PA-producing
plants contaminate crops, toxins can be transferred through the food chain and
cause illness in humans and animals, most notably hepatic veno-occlusive
disease. Honey has been identified as a direct risk of human exposure.

The
European Food Safety Authority has recently identified four groups of PAs that
are of particular importance for food and feed: senecionine-type,
lycopsamine-type, heliotrine-type and monocrotaline-type. Liquid or gas
chromatography methods are currently used to detect PAs but there are no rapid
screening assays available commercially. Therefore, the aim of this study was
to develop a rapid multiplex ELISA test for the representatives of three groups
of alkaloids (senecionine, lycopsamine and heliotrine types) that would be used
as a risk-management tool for the screening of these toxic compounds in food
and feed. The method was validated for honey and feed matrices and was
demonstrated to have a detection capability less than 25 μg/kg for jacobine,
lycopsamine, heliotrine and senecionine. The zinc reduction step introduced to
the extraction procedure allows for the additional detection of the presence of
N-oxides of PAs.

This first multiplex immunoassay for PA detection with N-oxide
reduction can be used for the simultaneous screening of 21 samples for >12
PA analytes. Honey samples (n = 146) from various origins were analysed for PA
determination. Six samples were determined to contain measurable PAs >25
μg/kg by ELISA which correlated to >10 μg/kg by LC-MS/MS.